in the processing of produce and vegetables, it is common to dip the vegetables in chilled water at 34.degree. F. with a slight trace of chlorine, usually 60 parts per million, to preserve the vegetables. After the vegetables are dipped, excess moisture must be removed from the vegetables to prevent rot. In the past, this drying operation has been performed in devices of the type manufactured by the Bock Company of Toledo, Ohio and identified as centrifuges.
A typical centrifuge of the type used to dry vegetables includes an open topped tub with holes in the side and bottom, much like the tub of a conventional home washing machine, which is filled with the produce to be dried. This tub is inserted through the top of an apparatus which spins the tub around a vertical axis at a high rotational speed, usually 1200 rpm. The centrifugal force exerted on the vegetables at this rotational velocity will cause excess moisture to be flung outward, through the holes in the tub, for removal.
A number of disadvantages exist in the apparatus currently used. The weight of the vegetables to be dried and the tub in which they are placed is commonly over 300 pounds, which requires an overhead crane or similar lifting apparatus to install and remove the drum and vegetables. Further, the area surrounding such machines is almost invariably wet and slippery because of the operation and is an unpleasant and potentially dangerous environment for workers. Also, as the vegetables are stacked within the tub from the vertical axis of rotation to the tub wall, the vegetables near the tub wall tend to be crushed by the centrifugal forces generated, leading to the possibility of damaging the vegetables.
A need exists for a mechanism to more effectively dry vegetables after water chilling. It would also be of significant benefit to be able to control the degree of moisture removal precisely to accommodate the particular vegetable moisture content most suitable for preservation of the particular vegetable being dried. Finally, a machine of such design could have wide applications in drying materials other than vegetables, for example, sewage and sludge, where moisture removal is an essential step in the treatment process.